Guide to Inspections of Low Acid Canned Food 31
Manufacturers - 2
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temperature. If the temperature drop was 10° F or more the reel must be stopped and all of the containers must be given a still process as above, discharged and reprocessed, repacked and reprocessed or discarded. If the temperature drop was less than 10° F., an authorized emergency still process may be used prior to restarting the reel, or container entry to the retort can be stopped and and authorized emergency agitating process used. Complete records of the handling of temperature drops must be made.
These systems may be installed with modifications which will allow unique processing to take place. Known system modifications include: the addition of dual spiral construction which allows for the processing of two container sizes at the same time using the same processing conditions; the use of metal carriers to hold and transport glass containers through the system; the use of steam air mixtures to thermally process lacf; and the use of the continuous retort system as a water immersion retort with steam over-pressure. When modified continuous cookers are encountered the investigator must insure that the retort installation and operation meets the requirements of the firms filed scheduled process and the lacf regulations.
DISCONTINUOUS AGITATING STEAM RETORTS
Equipment and procedures for pressure processing in steam in discontinuous agitating retorts are covered by 21CFR 113.40(d) of the lacf regulations.
These retort systems are batch systems which provide for either continuous axial agitation of the product or end over end agitation of the product during thermal processing and cooling of the containers. The most common axial agitation batch retort in the United States is the FMC Orbital (Orbitort) Sterilizer. This system was designed to process large institutional size (#10) cans of medium viscosity products such as cream style corn. Other sizes of cans can be processed with modifications to the system.
The orbital sterilizer does its pressure processing and cooling in one shell. The sterilizer consists of a horizontal retort shell which contains an outer reel to which a spiral has been attached, and an inner reel which contains the container channels or steps.
During loading, cans are fed into the retort through a large air-operated gate valve located high on the retort wall. The outer spiral reel is locked to the retort shell. The inner reel is turning during loading causing the containers to move toward the exit end of the sterilizer. A counter keeps track of the number of containers loaded into the retort. A second counter advances the cans two turns separating processed and unprocessed cans by two spiral turns. This is a safety factor to keep unprocessed and processed cans separate. At the same time that containers are being loaded, processed containers are being unloaded through an air-operated gate valve located low on the exit end of the retort shell. When the retort is full the loading/unloading gates are closed, the outer "spiral" reel is locked to the inner "channel" reel holding the containers in place during thermal processing and cooling.
The retort is vented per the processing authority or equipment manufacturers recommendations. Documentation that adequate venting is achieved must be kept on file by the processor. At the time that steam is turned on, the drain must be left open for sufficient time to remove the steam condensate from the retort, and provision should be made for continuing drainage of the condensate during the retort operation. It is important to remove the condensate so that the containers do not contact condensate build up in the bottom of the retort which could cool the containers during thermal processing.
During thermal processing any air coming in with the steam is removed from the retort through bleeders located within one foot of the outermost container on each end of the retort and no more than 8 feet apart along the top of the retort or through some other arrangement proven to be satisfactory by temperature distribution studies.
At the conclusion of the thermal processing cycle, cooling water is introduced into the retort while the containers are still being agitated. When the product is cooled the retort is ready for emptying and reloading.
The product agitation in this retort system is produced by forcing the head space bubble through the product at very high (approximately 35 RPM) reel speeds. High speed rotation is possible because the containers are locked in place. The speed of the retort must be adjusted as necessary to agree with the speed of the retort listed in the filed scheduled process. The rotational speed as well as the process time must be recorded for each retort load. A recording tachometer may be used to provide a continuous record of retort rotational speed. If a tachometer is used the tachometer should be checked with a stop watch on a routine basis. A means of preventing unauthorized speed changes is required by the lacf regulations.
Factors critical to obtaining the induced agitation in these systems include: maintaining the correct headspace, product consistency, minimum machine vacuum in vacuum packed products, maximum fill-in or drained weight, and percent solids as specified in
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